Minimum quantity lubrication thread tap

ABSTRACT

A thread tap includes a shaft and teeth. The shaft includes helical passages from the threading end to the base end of the shaft. Each passage opens through an aperture in the threading end. A second tap includes a cap and the shaft includes an axially extending passage. The cap is coupled to the threading end and at least partially defines apertures in fluid communication with the passage and the exterior of the tap. A third tap includes teeth spaced apart by a plurality of linear flutes. The shaft includes a central passage and a plurality of flute passages. Each flute passage extends radially outward from a common location in the central passage to a corresponding one of the flutes. The central passage is closed to a terminal end of the threading end.

FIELD

The present disclosure relates to minimum quantity lubrication threadtap.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Conventional thread taps use high volume flow of a liquid lubricant overthe cutting edges of the tool. Some thread taps have an internal passagethat provide this liquid lubricant to each cutting edge. Since theliquid lubricant is essentially an incompressible fluid, flow from thepassage to each cutting edge remains substantially based on the pressureof the liquid supplied to the tool.

In contrast, minimum quantity lubrication (“MQL”) machining useslubrication supplied to the cutting edges of a tool through a leanair-oil mist, rather than through the high volume liquid-based emulsionin conventional thread tapping. The ratio of air to oil in the air-oilmist is typically very high and the lubricant mist acts as acompressible fluid (unlike the incompressible liquid lubricant ofconventional thread tapping). Taps designed for liquid lubricant flowthrough internal passages suffer from excessive air compression andbackpressure when used with the air-oil mist of MQL machining. This canresult in wasted lubricant and excess wear on the tap.

The present disclosure provides a thread tap having a more balancedlubrication flow for MQL thread tapping that overcomes the problems oftypical thread taps when used for MQL tapping.

SUMMARY

In one form, a thread tap includes a shaft and a plurality of teethdisposed at a threading end of the shaft. The shaft includes a pluralityof passages that extend helically from the threading end to a base endof the shaft opposite the threading end. Each passage is open through acorresponding aperture defined by the threading end.

According to a further form, the corresponding apertures are equallyspaced apart in a circumferential direction about a central axis of theshaft.

According to a further form, the corresponding apertures are defined bya terminal end face of the threading end or a tapered end face of thethreading end.

According to a further form, the corresponding apertures are configuredto release lubricant in opposite directions from the terminal end faceof the threading end toward the teeth.

According to a further form, the base end of the shaft includes amanifold chamber in fluid communication with each passage.

According to a further form, a helical pitch of the passages is adifferent pitch than a thread pitch of the teeth.

According to a further form, a helical diameter of the passages is lessthan a minimum diameter of the teeth.

According to a further form, sets of the teeth are spaced apart byflutes defined by the shaft.

According to a further form, the flutes extend linearly along the shaft.

According to a further form, the passages are radially inward of theflutes.

In another form, a thread tap includes a shaft, a cap, and a pluralityof teeth disposed at a threading end of the shaft. The shaft includes anaxially extending passage open through the threading end. The cap iscoupled to the threading end and at least partially defines a pluralityof apertures in fluid communication with the passage and an exterior ofthe thread tap.

According to a further form, the cap includes a deflecting body and aplurality of supports. The supports couple the deflecting body to thethreading end. The apertures are disposed between the supports.

According to a further form, the plurality of apertures are equallyspaced apart in a circumferential direction about a central axis of theshaft.

According to a further form, the cap includes a deflecting body coaxialwith a central axis of the shaft. The deflecting body narrows in anaxial direction toward the passage to direct fluid from the passageradially outward.

According to a further form, the cap is mounted to the shaft.

According to a further form, the cap is mounted to a terminal end of thethreading end by epoxy, brazing, welding, or press-fit contact.

In another form, a thread tap includes a shaft and teeth spaced apart bya plurality of flutes that extend linearly along a threading end of theshaft. The shaft includes a central passage and a plurality of flutepassages. Each flute passage extends radially outward from a commonlocation in the central passage to a corresponding one of the flutes.The central passage is closed to a terminal end of the threading end.

According to a further form, each flute passage is open to thecorresponding flute at a tapered portion of the threading end.

According to a further form, the plurality of flutes consists of a firstflute and a second flute. The plurality of flute passages consists of afirst flute passage and a second flute passage. The first and secondflutes extend linearly along the shaft.

According to a further form, the first flute passage has a diameter d1,the second flute passage has a diameter d2, and the central passage hasa diameter Dc, and d₁=d₂=D_(c)/√(2).

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a perspective view of a thread tap in accordance with theteachings of the present disclosure;

FIG. 2 is perspective view of a base end of the thread tap of FIG. 1;

FIG. 3 is a side plan view of the thread tap of FIG. 1;

FIG. 4 is a perspective view of a thread tap of a second construction inaccordance with the teachings of the present disclosure, illustrating adeflecting cap;

FIG. 5 is a cross-sectional view of the thread tap of FIG. 4;

FIG. 6 is a perspective view of a deflecting cap of a secondconstruction in accordance with the teachings of the present disclosure;

FIG. 7 is perspective view of a thread tap of a third construction inaccordance with the teachings of the present disclosure; and

FIG. 8 is a cross-sectional view of the thread tap of FIG. 7.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

With reference to FIG. 1, a thread tap 10 of a first construction isillustrated. The tap 10 includes a shaft 14 and a plurality of externalteeth 18. The shaft 14 is disposed coaxially about a central axis 22 andhas a holding portion 26 and a tapping portion 30 that is axiallyopposite the holding portion 26. The shaft 14 defines a plurality ofpassages 34, 38 that extend in a helical manner about the central axis22 through the holding portion 26 and the tapping portion 30. In theexample provided, there are two passages 34, 38 that maintain separatehelical paths through the holding portion 26 and the tapping portion 30,i.e., from a first end 42 of the shaft 14 to a second end 46 of theshaft 14.

The holding portion 26 is configured to be gripped by a tapping toolholder (not shown) that can rotate the tap 10 about the central axis 22.In the example provided, the holding portion 26 has a smooth cylindricalouter surface 50 and a frusto-conical surface 54 that extends axiallyfrom the cylindrical outer surface 50. The frusto-conical surface 54narrows in the axial direction toward the first end 42 (i.e., thefrusto-conical surface narrows with increased distance from the tappingportion 30). With additional reference to FIG. 2, the first end 42defines a manifold chamber 58 open through the tip of the frusto-conicalsurface 54 and in fluid communication with the passages 34, 38. Thefrusto-conical surface 54 and/or the cylindrical outer surface 50 areconfigured to seal with the tool holder (not shown) and the tool holderis configured to supply lubrication in the form of an air-oil mist(i.e., minimum quantity lubrication, “MQL”) to the passages 34, 38 viathe manifold chamber 58.

In the example provided, the tapping portion 30 has a smaller outerdiameter than the holding portion 26. The teeth 18 are external teethdisposed about the tapping portion 30 proximate to the second end 46.The teeth 18 extend helically about the axis 22. In the exampleprovided, the teeth 18 form a single start thread that winds helicallyabout the tapping portion 30. The teeth 18 have a minor diameter definedby valleys between threadforms and a major diameter defined by peaks ofeach threadform.

With additional reference to FIG. 3, the tapping portion 30 can have atapered or chamfered region 62 generally between the teeth 18 and thesecond end 46. In the example provided, the first few teeth 18 proximateto the second end 46 can also be within the chamfered region 62 suchthat the first few teeth 18 are chamfered threadforms. The chamferedregion 62 narrows toward the second end 46. In the example provided, thechamfered region 62 narrows to a diameter that is less than the minordiameter of the teeth 18.

The passages 34, 38 have a pitch (i.e., the distance along the axis 22that the helix takes to make one complete revolution about the axis 22)that is different than the pitch of the teeth 18. In the exampleprovided, the passages 34, 38 have a helical pitch that is significantlyless than the pitch of the teeth 18, such as a helix pitch of between15° and 30°, though other configurations can be used. In the exampleprovided, the passages 34, 38 have a constant helix radius (i.e., aconstant helix diameter). In other words, the passages 34, 38 maintain aconstant distance apart from the axis 22 throughout the shaft 14. Thehelix diameter is less than the minor diameter of the teeth 18 such thatthe passages 34, 38 remain completely radially inward of the teeth 18.In the example provided, the minor diameter of the teeth 18 is between 5mm and 14 mm, though other sizes can be used depending on the size ofthe hole (not shown) to be tapped and the size of threads desired.

The passages 34, 38 can be equally spaced apart in the circumferentialdirection. In the example provided, the two passages 34, 38 arediametrically opposite each other. Each passage 34, 38 is open throughthe tapping portion 30 at a corresponding aperture 66. In the exampleprovided, the chamfered region 62 narrows to a diameter that is lessthan the helix diameter so that the apertures 66 are open through thechamfered region 62 to provide lubrication at the chamfered region 62.In the example provided, the apertures 66 are diametrically oppositeeach other so that rotation of the tap 10 causes the lubrication to beexpelled from the passages 34, 38 in opposite directions radiallyoutward from the end face toward the teeth 18.

In an alternative configuration, not specifically shown, the chamferedregion 62 does not narrow less than the helix diameter and the apertures66 are open through the terminal end face of the second end 46. In thisalternative example, rotation of the tap 10 causes the lubrication to beexpelled from the passages 34, 38 in opposite directions radiallyoutward toward the teeth 18.

Returning to the example provided, the tap 10 is a forming tap and doesnot include any flutes or leading cutting edges. While not specificallyshown, the forming tap can include oil grooves extending axially alongthe shaft 14 through the peaks of the teeth 18, i.e., locations wherethe threadforms of the teeth 18 have been truncated without formingcutting edges. The apertures 66 can be aligned in the circumferentialdirection with corresponding ones of the oil grooves (not shown) to emitlubrication directly or indirectly to the grooves (not shown).

In an alternative configuration, not specifically shown, the tap 10 canbe a cutting tap including a plurality of flutes and leading cuttingedges at each flute. In this alternative configuration, the apertures 66can be aligned in the circumferential direction with corresponding onesof the flutes (not shown) to emit lubrication directly or indirectly tothe flutes (not shown).

With reference to FIGS. 4-6, a thread tap 410 of a second constructionis illustrated. The tap 410 includes a shaft 414, a plurality ofexternal teeth 418, and a cap 422. The shaft 414 is disposed coaxiallyabout a central axis 426 and has a holding portion 430 and a tappingportion 434 that is axially opposite the holding portion 430. The shaft414 defines a central passage or bore 438 that extends coaxially alongthe central axis 426 through the holding portion 430 and the tappingportion 434. The bore 438 is open through a first end 442 of the shaft414 and extends fully through the shaft 414 to be open through anopposite second end 446.

The holding portion 430 is configured to be gripped by a tapping toolholder (not shown) that can rotate the tap 410 about the central axis426. In the example provided, the holding portion 430 has a smoothcylindrical outer surface 450. In the example provided, the outersurface 450 is configured to seal with the tool holder (not shown) andthe tool holder is configured to supply lubrication in the form of anair-oil mist (i.e., minimum quantity lubrication, “MQL”) to the bore 438through the first end 442.

In the example provided, the tapping portion 434 has a smaller outerdiameter than the holding portion 430. The teeth 418 are external teethdisposed about the tapping portion 434 proximate to the second end 446.The teeth 418 extend helically about the axis 426. In the exampleprovided, the teeth 418 form a single start thread that winds helicallyabout the tapping portion 434. The teeth 418 have a minor diameterdefined by valleys between threadforms and a major diameter defined bypeaks of each threadform.

The tapping portion 434 can have a tapered or chamfered region 454generally between the teeth 418 and the second end 446. In the exampleprovided, the first few teeth 418 proximate to the second end 446 canalso be within the chamfered region 454 such that the first few teeth418 are chamfered threadforms. The chamfered region 454 narrows towardthe second end 446. In one configuration, the chamfered region 454 cannarrow to a diameter that can be less than the minor diameter of theteeth 418, though other configurations can be used.

The cap 422 is fixedly (i.e., non-movably) mounted to the second end 446and is generally configured to deflect MQL flow from the bore 438radially outward toward the teeth 418. In the example provided, the cap422 includes a deflector body 458 and a plurality of supports 462. Thedeflector body 458 has a shape configured to direct lubrication flowfrom the bore 438 radially outward. In the example provided, thedeflector body 458 has a generally conical shape coaxial with the axis426. The base of the conical deflector body 458 is spaced axially apartfrom the second end 446 and the deflector body 458 narrows toward itstip proximate to the second end 446. In the example provided, the tip ofthe conical deflector body 458 extends within the bore 438, though otherconfigurations can be used. While illustrated in FIG. 5 as a generallyconical shape, other shapes can be used, e.g., a pyramid, afrusto-conical shape, or a curved surface (e.g., as shown in FIG. 6).

The supports 462 are radially outward of the bore 438 and extend fromthe base of the deflector body 458 in the axial direction toward thesecond end 446. The supports are fixedly attached to the tapping portion434. The supports 462 are spaced apart in the circumferential directionto define apertures or openings between the supports 462. In the exampleprovided, there are four supports 462 equally spaced apart to definefour openings, though other numbers of supports 462 can be used. In theexample provided, the second end 446 defines four mounting recesses 466that correspond to the four supports 462. Each recess 466 is openthrough the terminal face of the second end 446 and disposed radiallyoutward of the bore 438. Each support 462 is received in a correspondingone of the recesses 466 and fixed therein. In the example provided, thesupports 462 are press-fit in the recesses 466.

In an alternative configuration, not specifically shown, the supportscan be adhered within the recesses 466, such as with an epoxy forexample. In another alternative configuration, not specifically shown,the supports 462 can be welded or brazed in the recesses 466 or to thesecond end 446 absent the recesses 466.

Returning to FIGS. 4 and 5, the cap 422 is disposed entirely radiallyinward of the chamfered region 454 and radially inward of the minordiameter of the teeth 418. In the example provided, the cap 422 can bemade of a material that is softer than the shaft 414 since the cap 422does not contact the workpiece (not shown) during tapping. For example,the cap 422 may be made from plastic, powder metal, or low carbon steel.Accordingly, the cap 422 can be made using an inexpensive process, suchas injection molding, blanking/forging, or sintering for example.

In the example provided, the tap 410 is a forming tap and does notinclude any flutes or leading cutting edges. In the example provided,the forming tap can include oil grooves 470 extending axially along theshaft 414 through the peaks of the teeth 418, i.e., locations where thethreadforms of the teeth 418 have been truncated without forming cuttingedges. The openings between the supports 462 can be aligned in thecircumferential direction with corresponding ones of the oil grooves 470to emit lubrication toward the grooves 470. In an alternativeconfiguration, the tap 410 can be configured without the oil grooves470.

In an alternative configuration, not specifically shown, the tap 410 canbe a cutting tap including a plurality of flutes and leading cuttingedges at each flute. In this alternative configuration, the openingsbetween the supports 462 can be aligned in the circumferential directionwith corresponding ones of the flutes (not shown) to emit lubricationdirectly or indirectly to the flutes (not shown).

With reference to FIG. 6, an alternative configuration of the cap isillustrated and indicated with reference numeral 422′. The cap 422′ issimilar to the cap 422 (FIGS. 4 and 5), except as otherwise shown ordescribed herein. Elements denoted by primed reference numerals aresimilar to the elements shown and described in FIGS. 4 and 5 havingsimilar non-primed numerals, except as otherwise shown or describedherein.

Instead of a conical shape, the deflector body 458′ has a curved,concave surface 610 that directs the lubrication radially outward. Theconcave surface 610 is axisymmetrically curved with a central peak 614at the axis 426 and a variable radius of curvature that increases withradial distance from the axis 426 to a base 618. In the exampleprovided, the curvature is generally parabolic in shape, though otherconfigurations can be used. In one configuration, the radius ofcurvature at the center is between 2 and 4 times the tap major diameterand increases by roughly a factor of two or the major diameter withincreased radial distance from the axis 426. In the example provided,the deflector body 458′ can optionally have directing features such asrecesses, valleys or channels 622 configured to improve MQL deliveryradially outward to the teeth 418 (FIGS. 4 and 5), especially when thetap 410 rotates at high speeds (i.e., high revolutions per minute). Thechannels 622 can cause the deflector body 458′ to act as a centrifuge orcentrifugal pump, e.g., increasing centrifugal force acting on the MQLmixture to whip the MQL mixture radially outward toward the teeth 418(FIGS. 4 and 5). The channels 622 can optionally spiral about the axis426 depending on the rotational direction of the teeth 418 (FIGS. 4 and5) and thus the rotational direction of the tap 410 (FIGS. 4 and 5). Inthe example provided, the channels spiral in a clockwise manner from thecentral peak 614 to the base 618. In an alternative configuration, notspecifically shown, the channels 622 can spiral in a counter-clockwisedirection from the peak 614 to the base 618. In another alternativeconfiguration, not specifically shown, protrusions (e.g., fins) canprotrude from the concave surface 610 to direct the flow. Theprotrusions (not shown) can spiral about the axis 426 similar to thechannels 622.

With reference to FIGS. 7 and 8, a thread tap 710 of a thirdconstruction is illustrated. The tap 710 includes a shaft 714 and aplurality of external teeth 718. The shaft 714 is disposed coaxiallyabout a central axis 722 and has a holding portion 726 and a tappingportion 730 that is opposite the holding portion 726. The shaft 714defines a central passage or bore 734 and a plurality of branch passagesor bores 738. The central bore 734 extends coaxially along the centralaxis 722 through the holding portion 726 and a region of the tappingportion 730. The bore 734 is open through a first end 742 of the shaft714 at the holding portion 726 and extends through the shaft 714 towardan opposite second end 746, but is not open through the second end 746.

The holding portion 726 is configured to be gripped by a tapping toolholder (not shown) that can rotate the tap 710 about the central axis722. In the example provided, the holding portion 726 has a smoothcylindrical outer surface 750. In the example provided, the outersurface 750 is configured to seal with the tool holder (not shown) andthe tool holder is configured to supply lubrication in the form of anair-oil mist (i.e., minimum quantity lubrication, “MQL”) to the bore 734through the first end 742.

In the example provided, the tapping portion 730 has a smaller outerdiameter than the holding portion 726. The teeth 718 are external teethdisposed about the tapping portion 730 proximate to the second end 746.The teeth 718 extend helically about the axis 722. In the exampleprovided, the teeth 718 form a single start thread that winds helicallyabout the tapping portion 730. The teeth 718 have a minor diameterdefined by valleys between threadforms and a major diameter defined bypeaks of each threadform.

The tapping portion 730 can have a tapered or chamfered region 754generally between the teeth 718 and the second end 746. In the exampleprovided, the first few teeth 718 proximate to the second end 746 canalso be within the chamfered region 754 such that the first few teeth718 are chamfered threadforms. The chamfered region 754 narrows towardthe second end 746. In one configuration, the chamfered region 754 cannarrow to a diameter that can be less than the minor diameter of theteeth 718, though other configurations can be used.

In the example provided the tapping portion 730 includes a pair ofgrooves or channels 758 that are diametrically opposite each other andopen in the direction radially outward relative to the axis 722. Thechannels 758 extend linearly from the second end 746, toward the firstend 742, through the teeth 718, and terminate axially between the teeth718 and the holding portion 726. In the example provided, the channels758 have troughs that are radially inward of the minor diameter of theteeth 718, though other configurations can be used. In the exampleprovided, the tap 710 is a forming tap and the channels 758 are oilgrooves, such that the teeth 718 do not have cutting edges at theirinterface with the channels 758. In an alternative configuration, notspecifically shown, the tap 710 can be a cutting tap and the channels758 can be flutes such that the teeth 718 have leading cutting edges ateach flute.

The branch bores 738 extend from a terminal end of the central bore 734at an angle such that the branch bores 738 extend radially outward andaxially toward the second end 746. The branch bores 738 intersect thecentral bore 734 at a common location that is axially positioned withinthe region of the tapping portion 730 that includes the teeth 718 sothat the branch bores 738 are in fluid communication with the centralbore 734. The branch bores 738 are straight and form an obtuse angle 762with the central bore 734. The branch bores 738 are open through thetapping portion 730 to provide lubrication to the teeth 718 viaapertures 766.

In the example provided there are two branch bores 738 that arediametrically opposite each other and aligned with the channels 758. Theapertures 766 are disposed within the channels 758 to providelubrication directly to the channels 758. In the example provided, theangle 762 formed by the branch bores 738 is at least 135° and the angle762 can be greater than 150° depending on the length of the tappingportion 730. In the example provided, the branch bores 738 open to thechannels 758 at a location within the chamfered region 754. In analternative configuration, not specifically shown, the branch bores 738can open to the channels 758 at a location not in the chamfered region754, i.e., being open in the same axial region of the channels 758 wherethe teeth 718 would have their full major diameter. In the exampleprovided, the branch bores 738 each have a diameter that is equal to thediameter of the central bore 734 times the square root of two. In otherwords, d₁=d₂=D_(c)/√(2), where d₁ and d₂ are the diameters of the branchbores 738 and D_(c) is the diameter of the central bore 734. This ratioof diameters provides an equalized area for flow of the lubrication.

In an alternative configuration, not specifically shown, the centralbore 734 extends fully through the second end 746, but is plugged by aplug (not shown). The plug (not shown) seals the central bore 734 at thesecond end 746 to prevent lubrication from exiting through the secondend 746. The plug (not shown) terminates within the central bore beforethe intersection of the branch bores 738 with the central bore 734 so asnot to inhibit flow from the central bore 734 to the branch bores 738.The plug (not shown) can be attached within the central bore 734 withany suitable manner, e.g., welded, brazed, adhesive, epoxy, or threadedinto the central bore 734.

The description of the disclosure is merely exemplary in nature and,thus, variations that do not depart from the substance of the disclosureare intended to be within the scope of the disclosure. Such variationsare not to be regarded as a departure from the spirit and scope of thedisclosure.

What is claimed is: 1-10. (canceled)
 11. A thread tap comprising: ashaft, a cap, and a plurality of teeth disposed at a threading end ofthe shaft, the shaft including an axially extending passage open throughthe threading end, the cap coupled to the threading end and at leastpartially defining a plurality of apertures that extend radially outwardthrough a circumferential perimeter of the cap, the apertures being influid communication with the passage and an exterior of the thread tapsuch that lubricant is permitted to exit in a radially outward directiondirectly from the cap.
 12. The thread tap of claim 11, wherein the capincludes a deflecting body and a plurality of supports, the supportscoupling the deflecting body to the threading end, the apertures beingdisposed between the supports.
 13. The thread tap of claim 11, whereinthe plurality of apertures are equally spaced apart in a circumferentialdirection about a central axis of the shaft.
 14. The thread tap of claim11, wherein the cap includes a deflecting body coaxial with a centralaxis of the shaft, wherein the deflecting body narrows in an axialdirection toward the passage to direct fluid from the passage radiallyoutward.
 15. The thread tap of claim 14, wherein the deflecting bodyincludes protrusions or channels.
 16. The thread tap of claim 11,wherein the cap is mounted to a terminal end of the threading end byepoxy, brazing, welding, or press-fit contact. 17-20. (canceled)
 21. Thethread tap of claim 14, wherein the deflecting body has a parabolicshape disposed coaxially about a central axis of the shaft, theparabolic shape widening from a peak to a base, the base being furtherfrom the passage than the peak.
 22. The thread tap of claim 14, whereinthe deflecting body has a conical shape that widens from the peak to abase, the base being further from the passage than the peak.
 23. Thethread tap of claim 15, wherein the protrusions or channels spiral aboutthe central axis.
 24. The thread tap of claim 11, wherein each apertureof the plurality of apertures is aligned with a corresponding flute ofthe threading end.
 25. A thread tap comprising: a shaft having athreaded end defining a plurality of teeth, the shaft defining anaxially extending passage open through the threading end; a cap coupledto the threading end and at least partially defining a plurality ofapertures in fluid communication with the passage and an exterior of thethread tap, wherein the cap includes a deflecting body that narrows to apeak that is coaxial with the passage and faces toward the passage. 26.The thread tap of claim 25, wherein the cap includes a plurality ofsupports, the supports coupling the deflecting body to the threadingend, the apertures being disposed between the supports.
 27. The threadtap of claim 25, wherein the plurality of apertures are equally spacedapart in a circumferential direction about a central axis of the shaft.28. The thread tap of claim 25, wherein the passage is coaxial with theshaft.
 29. The thread tap of claim 28, wherein the deflecting bodyincludes protrusions or channels.
 30. The thread tap of claim 29,wherein the protrusions or channels spiral about a central axis of theshaft.
 31. The thread tap of claim 25, wherein the deflecting body has aparabolic shape disposed coaxially about a central axis of the shaft.32. The thread tap of claim 25, wherein each aperture of the pluralityof apertures is aligned with a corresponding flute of the threading end.33. The thread tap of claim 25, wherein the deflecting body has aconical shape that widens from the peak to a base, the base beingfurther from the passage than the peak.